Polymer materials typified by, for example, polyolefin resin-, polyester resin-, polyamide resin-, polyacrylate resin-, polycarbonate resin-, and polyimide resin-based materials have been widely utilized as various industrial materials. These general-purpose polymer materials have excellent mechanical and physical properties, such as heat resistance and impact resistance, but they hardly decompose in the environment and remain in the ground semipermanently when buried.
Biodegradable materials have been attracting attention in recent years, and the development of biodegradable resins, such as an aliphatic polyester resin, has been actively performed. Plant-derived resins have been attracting attention because of their potential to serve as carbon-neutral materials, because carbon dioxide produced by the decomposition of the resins may be such that carbon dioxide originally present in the air is immobilized.
Of the plant-derived resins, polylactic acid has been mainly applied to, for example, packages for OA systems and home appliances, automobile parts, bottles, films, sheets, and eating utensils. In general, however, high impact resistance is often needed in those applications. At present, it is difficult to use polylactic acid, which has extremely low impact resistance, in such applications, so the actual use of polylactic acid has been limited. There has been a growing demand from the industrial community for a plant-derived resin with improved impact resistance, because the resin can be expected to find use in a variety of applications. Accordingly, various kinds of approaches have been taken to improve the impact resistance of a plant-derived resin.
To be specific, a polyester resin using a plant-derived material has been reported as one approach to improving the impact resistance of a plant-derived resin (Japanese Patent Application Laid-Open No. 2007-146153).